Protein kinases regulate diverse biological processes including cell growth, survival, differentiation, organ formation, morphogenesis, neovascularization, tissue repair, and regeneration, among others. Protein kinases also play specialized roles in a host of human diseases including cancer. The three members of the Pim kinase family, one example of a protein kinase family, were initially identified as preferential integration sites of Moloney leukemia virus in mouse models of cancer. Although possessing modest but measurable oncogenic activity alone, they potentiate pro-proliferative and pro-survival oncogenes, e.g., causing a dramatic acceleration of lymphomagenesis in Myc-transgenic or Bcl2-transgenic mice. Mikkers et al., Nature Genet., 2002, 32, 153-159; Shinto et al., Oncogene, 1995, 11, 1729-35.
The three non-receptor serine/threonine kinases Pim1, Pim2 and Pim3 regulate cell proliferation and survival by impacting gene transcription and protein translation. Zippo, et al., Nature Cell Biol., 2007, 9, 932-44; Schatz, et al., J. Exp. Med., 2011, 208, 1799-1807. As opposed to numerous other protein kinases which require activation by phosphorylation, the Pim kinases are constitutively activated and family members have overlapping substrate targets and biological functions, with differences between family members dictated, in part, by their varied tissue distribution. Expression of the Pim kinases is induced by cytokines and growth factors. Among the cytokines activating Pim kinase expression are cytokines which signal through the JAK/STAT pathway. Pim kinases act in parallel to the PI3K/AKT pathway, and they share several phosphorylation targets (e.g., pBAD, p4EBP1). Inhibitors of Pim kinases may therefore potentiate regimens including inhibitors of either the JAK pathway or the PI3K/AKT pathway.
Overexpression of Pim kinases is detected in a wide variety of hematologic and solid cancers. Overexpression of various family members have been noted in multiple myeloma, AML, pancreatic and hepatocellular cancers. Claudio et al., Blood 2002, 100, 2175-86; Amson et al., Proc. Nat. Acad. Sci. USA, 1989, 86, 8857-61; Mizuki et al., Blood, 2003, 101, 3164-73; Li et al., Canc. Res., 2006, 66, 6741-7; Fujii et al., Int. J. Canc., 2005, 114, 209-18. Pim1 overexpression is associated with poor prognosis in mantle cell lymphoma, esophageal and head and neck cancers. Hsi et al., Leuk. Lymph., 2008, 49, 2081-90; Liu et al., J. Surg. Oncol., 2010, 102, 683-88; Peltola et al., Neoplasia, 2009, 11, 629-36. Pim2 overexpression is associated with an aggressive clinical course in a subset of DLBCL patients. Gomez-Abad et al., Blood, 2011, 118, 5517-27. Overexpression is often seen where Myc is overexpressed and Pim kinases can convey resistance to traditional chemotherapeutic agents and radiation. Chen et al., Blood, 2009, 114, 4150-57; Isaac et al., Drug Resis. Updates, 2011, 14, 203-11; Hsu et al., Cancer Lett., 2012, 319, 214; Peltola et al., Neoplasia, 2009, 11, 629-36.
As such, these data indicate that inhibition of Pim kinases will be useful to provide therapeutic benefit in cancer patients.
Data from mice deficient for one or multiple Pim kinase family members suggests that pan-Pim inhibitor would have a favorable toxicity profile. Triple knockout mice are viable, but are slightly smaller than their wild type littermates. Mikkers et al., Mol. Cell. Biol., 2004, 24. 6104-15. Since Pim kinases are also involved in a variety of immunologic and inflammatory responses and these indications require drug agents with fewer side effects, Pim kinase inhibitors are expected to be useful in treating patients with colitis (Shen et al., Dig. Dis. Sci., 2012, 57, 1822-31), peanut allergy (Wang et al., J. All. Clin. Immunol., 2012, 130, 932-44), multiple sclerosis and lupus (Davis et al., “Small Molecule Dual Antagonist of Pim 1 and 3 Kinases Ameliorate Experimental Autoimmune Encephalomyelitis”, 26th Congress of the European Committee for Treatment and Research in Multiple Sclerosis, 13-16 Oct. 2010, Gothenburg, Sweden, Poster P436; Robinson et al., J Immunol., 2012, 188, 119.9) and rheumatoid arthritis (Yang et al., Immunol. 2010, 131, 174-182), and other immunological and inflammatory disorders.
The Pim kinases have therefore been identified as useful targets for drug development efforts. Swords et al., Curr. Drug Targets, 2011, 12(14), 2059-66; Merkel et al., Exp. Opin. Investig. Drugs, 2012, 21, 425-38; Morwick et al., Exp. Opin. Ther. Patents, 2010, 20(2), 193-212.
Accordingly, there is a need for new compounds that inhibit Pim kinases. The present application describes new inhibitors of Pim kinases that are useful for treating diseases associated with the expression or activity of one or more Pim kinases, e.g., cancer and other diseases.